Tobacco curing apparatus

ABSTRACT

Apparatus for heating a tobacco barn in order to cure the tobacco rapidly and effectively is disclosed herein. The apparatus comprises in combination with the barn, a pair of heat exchangers, each exchanger being mounted on diagonally opposite walls of the barn, and a high speed fuel oil burner with continually operating blowers mounted in the exchanger end adjacent the barn wall. Each heat exchanger is connected to an axially extending duct and to a perpendicularly extending duct, the opposite ends of the two ducts being intraconnected with the other heat exchanger ducts so as to form a quadrilateral arrangement of ducts on the floor of the barn. Air diffusers are spacedly mounted at equal intervals on the upper sides of each of the aforementioned ducts and act to evenly distribute hot air into the barn.

United States Patent Remick Aug. 29, 1972 [54] TOBACCO CURING APPARATUS [72] Inventor: Karl F. Remick, Seaford, NY.

[73] Assignee: Cities Service Oil Company [22] Filed: Dec. 30, 1970 [21] Appl. No.: 102,746

Primary ExaminerJohn J. Camby Attorney-J. Richard Geaman [57] ABSTRACT Apparatus for heating a tobacco barn in order to cure the tobacco rapidly and effectively is disclosed herein. The apparatus comprises in combination with the barn, a pair of heat exchangers, each exchanger being mounted on diagonally opposite walls of the barn, and a high speed fuel oil burner with continually operating blowers mounted in the exchanger end adjacent the barn wall. Each heat exchanger is connected to an axially extending duct and to a perpendicularly extending duct, the opposite ends of the two ducts being intraconnected with the other heat exchanger ducts so as to form a quadrilateral arrangement of ducts on the floor of the barn. Air diffusers are spacedly mounted at equal intervals on the upper sides of each of the aforementioned ducts and act to evenly distribute hot air into the barn.

3 Claims, 3 Drawing Figures Patented Aug. 29, 1972 2 Sheets-Sheet 2 eo g2 94/ I a4\ I BURNNER -76 BURNNER .278 MOTOR I MOTOR 2 I f I PROTECTOR PROTECTOR RELAY! -86 RELAY 2 -88 96 I04 Io0- -IO2 I08 I VALVE \\OIL VALVE IGNITION IGNITION TRANS. I TRANS. 2

98 Ios- FIG. '3

I6 WALL 2 v INVENTOR.

I KARL F. REMICK .qBY FIG. 2 INSULATION I ATTORNEY TOBACCO CURING APPARATUS BACKGROUND OF THE INVENTION This invention relates to apparatus for efiiciently and effectively curing tobacco in a conventional tobacco curing barn. More particularly this invention relates to apparatus for utilizing fuel oil more economically to cure tobacco. Tobacco leaves after being picked, are dried or cured in order to remove a significant amount of moisture therefrom and to obtain the desirable texture, color, and taste that the buyer is looking for. To achieve this end, tobacco farmers merely strung the tobacco leaves on racks and allowed normal time and weather to cure the tobacco. This yielded somewhat unsatisfactory results in that the conditions were not controlled by the farmer and depended solely on available weather. Also curing in open air or closed barns takes an inordinate amount of time, thereby tieing up the space and the tobacco farmers crop. It has, therefore, become the practice to heat the curing area in order to drive off moisture from the leaves more rapidly. For this purpose burner pots, gas fuel space heaters and other auxilliary heating equipment have generally been employed. With the increasing cost of fuel and the desire of the tobacco farmer to obtain the best price possible for his crop, it has become necessary to consider more efficient means for curing tobacco.

SUMMARY OF THE INVENTION I have, therefore, invented an improved apparatus for curing tobacco stored in a barn. The curing apparatus comprises in combination with a barn, a pair of heat exchangers mounted adjacent to and parallel the barn floor, and extending from the walls of the barn. The first heat exchanger is mounted on a barn wall diagonally opposite the second heat exchanger mounting wall. Each heat exchanger has an outside end extending through the adjacent barn wall and a high speed fuel oil burner communicatingly attached to the outside end of each of the heat exchangers. The high speed fuel oil burners are commercially available and are controlled in a novel manner wherein the burner air blower is continuously operated. Each of the heat exchangers have an axially extending duct and a transversely extending duct also connected to the exchanger inside ends, both ducts being parallel to the floor of the barn. Each of the ducts extend for a length sufficient to contact the oppositely extending duct from the other heat exchanger and connect therewith. All the ducts have openings located at equally spaced intervals to allow the heated outside air to be uniformly distributed over the floor of the barn, thereby achieving a uniformity of curing not previously available.

It is, therefore, an object of the present invention to provide apparatus for curing tobacco.

Another object of the present invention is to provide apparatus for curing tobacco which provides a desirable uniformity to the cured tobacco product.

Still another object of the present invention is to provide efficient, economical, and simple apparatus for the rapid uniform curing of tobacco leaves.

Other objects and advantages of the present invention will be apparent to those skilled in the art from the brief description of the drawings, and the preferred embodiment which follow.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 of the drawing is a layout view of the tobacco curing apparatus of this invention;

FIG. 2 is a cross-sectional view of a heat exchanger;

FIG. 3 is a schematic drawing of the control portion of the tobacco curing apparatus of this invention.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS A conventional tobacco curing barn is a simple frame building resting on a minimal cinder block or concrete foundation and having an earthen floor. The building is generally around 16 feet square, possesses no insulation or interior finishing and has the tobacco leaves supported on racks, with the lowest racks being about 4 feet or so off the floor. The barn is generally sealed during the curing period and modified for the particular type of heating apparatus which is used during the curing operation. Examples of the prior art heating apparatus which have been used are: conventional gas or liquid petroleum gas fired space heaters which are placed in the center of the building and provide heat with which to rapidly dry and cure the tobacco leaves; simple smoke pots or burners which have stacks that pass through the roof of the building; or in the earlier types of curing operations merely the building of a wood fire on the floor of the barn during the curing operation.

The existing barn designated herein as 12 is easily modified to accomodate the tobacco curing apparatus of the present invention. This is achieved by boring a hole 14 about a foot and a half in diameter, and several inches above the ground level in the barn foundation wall and mounting therein a first heat exchanger 16. The heat exchanger 16 is mounted off to one side of the center of the building wall at a distance from the edge which corresponds to about one-quarter the length of the wall. As shown the heat exchanger therefore extends through the foundation wall of the barn so that one end is flush with the outside surface of the foundation. Attached to the outside end of the heat exchanger is a high speed conventional oil burner 18. The high speed burner 18 is a fuel oil burner having a blower motor which operates in the neighborhood of about 3,500 rpm. causing the blower rotor and the blast tube of the burner to produce a positive pressure in the heat exchanger.

The heat exchanger 16 is a cylindrically shaped enclosure which is internally lined with a heat resistant insulation material such as kaowool or other similar materials and is preferably divided into two chambers, a combustion chamber 20 adjacent the blast tube of the high speed oil burner, and a plenum chamber 24. The two chambers are formed by a dividing partition 26 in the form of an annular ring having a hole 28 located therein. Heated air and combustion products are directed into a pair of ducts attached to the plenum chamber 24 of the heat exchanger. An end plate 29 forms the plenum end of the heat exchanger and has an offset port 30 therein to which an axially extending duct 32 is attached. The axially extending duct 32 has a length of over one-half of the width of the barn wall to which it is parallel and extends axially away from the attached heat exchanger. An air distribution port 34 is located midway along its length on the upper side in the form of a 6-inch rain cap and thimble assembly 36 of conventional design. At the far end of the axially extending duct 32 an upwardly extending smoke elbow 38 is mounted with a raincap 40 attached to the top of the elbow. Just before the elbow 38 the duct 32 has inserted therein a smoke T 42 also of conventional manufacture which has perpendicularly extending takeoff connection 44.

Another duct designated herein as a transverse duct 46 is connected to each heat exchanger plenum chamber wall at a point on the plenum cylindrical wall adjacent the heat exchanger end. The transverse duct 46 extends parallel to the floor of the barn for a distance of about one-half the width of the barn wall to a second 6-inch smoke T 48. The second smoke T 48 is mounted in a second axially extending duct 50 connected to a second heat exchanger 52 in a similar manner to the first exchanger and ducts. A discharge port 54 is located at the top of the duct 46 at the middle thereof, and has a conventional raincap and thimble 56 extending up from the duct discharge port 54. The raincap and thimble assemblies act to diffuse the hot air exiting from the ducts.

Another duct designated herein as a transverse duct 46 is connected to each heat exchanger plenum chamber wall at a point on the plenum cylindrical wall adjacent the heat exchanger end. The transverse duct 46 extends parallel to the floor of the barn for a distance of about one-half the width of the barn wall to a second 6-inch smoke T 48. The second smoke T 48 is mounted in a second axially extending duct 50 connected to a second heat exchanger 52 in a similar manner to the first exchanger and ducts. A discharge port 54 is located at the top of the duct 46 at the middle thereof, and has a conventional raincap and thimble 56 extending up from the duct discharge port 54. The raincap and thimble assemblies act to diffuse the hot air exitir'lg from the ducts.

The second heat exchanger 52 is constructed in exactly the same manner as the first and is mounted on an opposite wall of the barn at the base thereof at a point diagonally opposite the first heat exchanger 16..The second heat exchanger is constructed in a similar manner to the first heat exchanger 16 and has all the same features and connections except for its position within the barn. The second heat exchanger is therefore mounted on the diagonally opposite wall of the barn from the first heat exchanger and at a distance of about one-half the wall width from the first heat exchanger. The second exchanger is cylindrical in shape and has a second high speed oil burner similar to the first high speed oil burner mounted on the outside face thereof and is also internally lined with an insulation material such as kaowool. Similarly the second heat exchanger is divided into a combustion chamber and a plenum by an annular partition in the same manner as the first heat exchanger. Extending axially out from the inside end of the heat exchanger through a port in the end wall is the second axially extending duct 50 which runs along the floor of the barn and is connected to by the second smoke T 48 to the first transversely extending duct 46. A second smoke elbow 58 is connected to the end of the second axially extending duct and ends in a raincap mounted thereon in the 50 and at the other end to the first axial duct at the first smoke T 42.

The second transverse duct 62 also has a port 64 located on the upper side of the midpoint with a thimble with a raincap mounted thereon for distributing heated air into the barn. It is, therefore, readily apparent that in the embodiment described herein there are six air discharge ports for uniformly distributing the air throughout the barn, with the only blank spaces being located at the point where each of the heat exchangers are connected to the respective ducts. The lack of air outlet adjacent the heat exchangers does not result in a complete elimination of heat input at their locations in the barn since the heat exchangers themselves act as sources of heat by conduction.

Referring now to FIG. 3 of the drawing wherein a schematic diagram for control of the tobacco curing apparatus is shown, electrical power is conventionally supplied through hot line and ground line 72 from a source, not shown. A conventional on-off switch 74 is' mounted in the hot line for emergency shut-off purposes. The hot and ground lines are connected in parallel to the first burner motor 76 and to the second burner motor 78 by line 80 connected to the hot line 70 and line 82 connected to the ground line 72. Both m0- tors are, therefore, in continuous operation during the tobacco curing process. Each of the motors continually power the blower in each of the oil burners.

A line 84 is also connected in parallel to a first and a second protector relay respectively 86 and 88. Another line 90 extends from a junction with hot line 70 to a temperature responsive crop controller 92 operating in the range of from 80 to 220 E. The controller 92 is merely an automatic switch which may be turned on manually or in timed sequence and which operates automatically to maintain the area adjacent the controller within a specific temperature setting plus or minus a small variation. The controller is inserted centrally in the barn at about eye-level height.

An output line 94 is connected in parallel from the controller to each of the protector relays 86 and 88. The protector relays each controls the operation of its respective high speed burner by opening or closing an oil valve to each of the burners and powering an ignition transformer to each burner at the same time. For this purpose the first protector relay 86 is connected in parallel to a first oil valve 96 and to a first ignitiontransformer 98 via lines 100 and 102. The second protector relay 88 is similarly connected in parallel to a second oil valve 104 and a second ignition-transformer 106 via lines 108 and 110. Thus, upon being activated by the controller 92 both relays in turn open their respective valve and transformer to provide a continuous spark ignition of the oil exiting through the nozzle of the burner. Therefore, it is clearly seen that fuel oil flow through the burner and ignition thereof are responsively controlled by the controller.

In operation, the burner motor blowers are continually operating forcing air from the outside of the barn in through the respective heat exchangers and finally into the barn space. When the controller senses a lower than desired curing temperature, the two oil valves and ignition transformers are activated causing fuel oil to be sprayed from the burner nozzle into the combustion chamber, at the same time igniting the oil. The oil is mixed with the air being continually forced into the plenum chamber and from there through the respective ducts into the barn space. Thus, when the controller senses that the barn temperature is undesirably high for curing, the respective oil valves and ignition transformers are deactivated and fuel oil is no longer passed into the burner, while air is still being forced at a relatively fixed rate through the burner blowers and into the barn. This feature of continually introducing outside air rather than recirculating internal air into the barn is decidely more effective since the outside air has considerably less moisture per cubic foot than the air in the barn. Thus, the operation of the apparatus of the present invention provides for faster curing or dehydration of the tobacco leaves.

As a result of employing the apparatus of this invention tobacco is more unifonnly cured within the barn regardless of the location of the particular leaves. Also because the apparatus occupies only floor space to a limited height, no space need be taken away for racking the tobacco leaves to be cured within the barn. Finally there is a shortening of the time period to cure the tobacco since a greater extent of moisture is removed from the tobacco leaves as a result of the utilization of the high temperatures and the outside drier air than if the inside of the barn was merely heated as in conventional practice.

Having described my invention and wishing to cover those modifications and variations which would be apparent to those skilled in the art without departing from either the scope or spirit of the invention.

1 claim:

1. Apparatus for curing tobacco stored in a barn said apparatus comprising,

a pair of heat exchangers mounted adjacent the barn floor, a first heat exchangers being mounted on a barn wall diagonally opposite 'a second heat exchanger, each heat exchanger extending through an opening in said barn walls,

a first and second high speed fuel oil burner communicatingly attached to each of said heat exchangers adjacent said wall openings each of said burners having a continuously operating air blower drawing air from outside the barn, and a burner nozzle extending into each of said heat exchangers,

each of said heat exchangers being connected to an axial duct mounted parallel to the barn floor and extending axially away from the inside end of each of said exchangers, and

transversely extending ducts each transverse duct being connected at one end to the end of each of said heat exchangers and at the other end to each of said first heat exchanger axial ducts each transverse duct, and axial duct having at least one outlet opening into the barn.

2. The apparatus of claim 1 wherein said fuel oil burners are responsively actuated by a co troller, s id control er being mounted within said am an being responsive to the temperature of air within said barn.

3. The apparatus of claim 2 wherein each of said heat exchangers are divided into a combustion chamber and a plenum chamber by a transversely mounted annular partition. 

1. Apparatus for curing tobacco stored in a barn said apparatus comprising, a pair of heat exchangers mounted adjacent the barn floor, a first heat exchanger being mounted on a barn wall diagonally opposite a second heat exchanger, each heat exchanger extending through an opening in said barn walls, first and second high speed fuel oil burners communicatingly attached to each of said heat exchangers adjacent said wall openings each of said burners having a continuously operating air blower drawing air from outside the barn, and a burner nozzle extending into each of said heat exchangers, each of said heat exchangers being connected to an axial duct mounted parallel to the barn floor and extending axially away from the inside end of each of said exchangers, and transversely extending ducts each transverse duct being connected at one end to the end of each of said heat exchangers and at the other end to each of said first heat exchanger axial ducts each transverse duct, and axial duct having at least one outlet opening into the barn.
 2. The apparatus of claim 1 wherein said fuel oil burners are responsively actuated by a controller, said controller being mounted within said barn and being responsive to the temperature of air within said barn.
 3. The apparatus of claim 2 wherein each of said heat exchangers are divided into a combustion chamber and a plenum chamber by a transversely mounted annular partition. 